One of the light transmitter-receivers known to public includes a rigid substrate and a package accommodating a light modulator that modulates, based on a signal input from the rigid substrate, light (see, for example, Patent Literature 1). As illustrated in FIG. 1, a light transmitter-receiver 90 includes a flexible substrate 95 that couples a first terminal 92 being provided on the surface of a rigid substrate 91 and a second terminal 94 protruding from a side wall of a package 93.
One end 96 of the flexible substrate 95 is coupled to the second terminal 94. A third terminal 98 is disposed on the surface of the other end 97 of the flexible substrate 95. The flexible substrate 95 is bent in such a posture that the third terminal 98 comes into contact with the first terminal 98 under a state where the third terminal 98 is positioned in parallel with the first terminal 92. Consequently, the third terminal 98 is coupled to the first terminal 92.